Initial metal abstraction (noop)

src/Window.zig

@@ -36,7 +36,7 @@ const log = std.log.scoped(.window);
 const WRITE_REQ_PREALLOC = std.math.pow(usize, 2, 5);
 
 // The renderer implementation to use.
-const Renderer = renderer.OpenGL;
+const Renderer = renderer.Renderer;
 
 /// Allocator
 alloc: Allocator,

src/renderer.zig

@@ -7,11 +7,21 @@
 //! APIs. The renderers in this package assume that the renderer is already
 //! setup (OpenGL has a context, Vulkan has a surface, etc.)
 
+const builtin = @import("builtin");
+
 pub usingnamespace @import("renderer/size.zig");
+pub const Metal = @import("renderer/Metal.zig");
 pub const OpenGL = @import("renderer/OpenGL.zig");
 pub const Thread = @import("renderer/Thread.zig");
 pub const State = @import("renderer/State.zig");
 
+/// The implementation to use for the renderer. This is comptime chosen
+/// so that every build has exactly one renderer implementation.
+pub const Renderer = switch (builtin.os.tag) {
+    .macos => Metal,
+    else => OpenGL,
+};
+
 test {
     @import("std").testing.refAllDecls(@This());
 }

src/renderer/Metal.zig

@@ -0,0 +1,86 @@
+//! Renderer implementation for Metal.
+pub const Metal = @This();
+
+const std = @import("std");
+const glfw = @import("glfw");
+const font = @import("../font/main.zig");
+const terminal = @import("../terminal/main.zig");
+const renderer = @import("../renderer.zig");
+const Allocator = std.mem.Allocator;
+
+const log = std.log.scoped(.metal);
+
+/// Current cell dimensions for this grid.
+cell_size: renderer.CellSize,
+
+/// Default foreground color
+foreground: terminal.color.RGB,
+
+/// Default background color
+background: terminal.color.RGB,
+
+/// Returns the hints that we want for this
+pub fn windowHints() glfw.Window.Hints {
+    return .{
+        .client_api = .no_api,
+        // .cocoa_graphics_switching = builtin.os.tag == .macos,
+        // .cocoa_retina_framebuffer = true,
+    };
+}
+
+/// This is called early right after window creation to setup our
+/// window surface as necessary.
+pub fn windowInit(window: glfw.Window) !void {
+    _ = window;
+}
+
+pub fn init(alloc: Allocator, font_group: *font.GroupCache) !Metal {
+    // Get our cell metrics based on a regular font ascii 'M'. Why 'M'?
+    // Doesn't matter, any normal ASCII will do we're just trying to make
+    // sure we use the regular font.
+    const metrics = metrics: {
+        const index = (try font_group.indexForCodepoint(alloc, 'M', .regular, .text)).?;
+        const face = try font_group.group.faceFromIndex(index);
+        break :metrics face.metrics;
+    };
+    log.debug("cell dimensions={}", .{metrics});
+
+    return Metal{
+        .cell_size = .{ .width = metrics.cell_width, .height = metrics.cell_height },
+        .background = .{ .r = 0, .g = 0, .b = 0 },
+        .foreground = .{ .r = 255, .g = 255, .b = 255 },
+    };
+}
+
+pub fn deinit(self: *Metal) void {
+    self.* = undefined;
+}
+
+/// This is called just prior to spinning up the renderer thread for
+/// final main thread setup requirements.
+pub fn finalizeInit(self: *const Metal, window: glfw.Window) !void {
+    _ = self;
+    _ = window;
+}
+
+/// Callback called by renderer.Thread when it begins.
+pub fn threadEnter(self: *const Metal, window: glfw.Window) !void {
+    _ = self;
+    _ = window;
+}
+
+/// Callback called by renderer.Thread when it exits.
+pub fn threadExit(self: *const Metal) void {
+    _ = self;
+}
+
+/// The primary render callback that is completely thread-safe.
+pub fn render(
+    self: *Metal,
+    window: glfw.Window,
+    state: *renderer.State,
+) !void {
+    _ = self;
+    _ = window;
+    _ = state;
+}

src/renderer/Thread.zig

@@ -31,7 +31,7 @@ render_h: libuv.Timer,
 window: glfw.Window,
 
 /// The underlying renderer implementation.
-renderer: *renderer.OpenGL,
+renderer: *renderer.Renderer,
 
 /// Pointer to the shared state that is used to generate the final render.
 state: *renderer.State,
@@ -42,7 +42,7 @@ state: *renderer.State,
 pub fn init(
     alloc: Allocator,
     window: glfw.Window,
-    renderer_impl: *renderer.OpenGL,
+    renderer_impl: *renderer.Renderer,
     state: *renderer.State,
 ) !Thread {
     // We always store allocator pointer on the loop data so that
@@ -143,16 +143,11 @@ pub fn threadMain(self: *Thread) void {
 }
 
 fn threadMain_(self: *Thread) !void {
-    // Get a copy to our allocator
-    // const alloc_ptr = self.loop.getData(Allocator).?;
-    // const alloc = alloc_ptr.*;
-
     // Run our thread start/end callbacks. This is important because some
     // renderers have to do per-thread setup. For example, OpenGL has to set
     // some thread-local state since that is how it works.
-    const Renderer = RendererType();
-    if (@hasDecl(Renderer, "threadEnter")) try self.renderer.threadEnter(self.window);
-    defer if (@hasDecl(Renderer, "threadExit")) self.renderer.threadExit();
+    try self.renderer.threadEnter(self.window);
+    defer self.renderer.threadExit();
 
     // Set up our async handler to support rendering
     self.wakeup.setData(self);
@@ -199,14 +194,3 @@ fn renderCallback(h: *libuv.Timer) void {
 fn stopCallback(h: *libuv.Async) void {
     h.loop().stop();
 }
-
-// This is unnecessary right now but is logic we'll need for when we
-// abstract renderers out.
-fn RendererType() type {
-    const self: Thread = undefined;
-    return switch (@typeInfo(@TypeOf(self.renderer))) {
-        .Pointer => |p| p.child,
-        .Struct => |s| s,
-        else => unreachable,
-    };
-}